dom4j对xml文档的操作（续）

<?xml version="1.0" encoding="UTF-8"?>

<书架>
<书>
<书名 name="jack">Java就业培训教程</书名>
<作者>张孝祥</作者>
<售价>88元</售价>
</书>
<书>
<书名>JavaScript网页开发</书名>
<作者>张孝祥</作者>
<售价>28.00元</售价>
</书>
</书架>

package com.dom4j;

import java.io.File;
import java.io.FileOutputStream;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;
import org.xml.sax.DocumentHandler;

public class Demo1 {

//在指定的地方添加标签或属性
@Test
public void add1() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book.xml"));

Element book = (Element) document.getRootElement().elements("书").get(1);
List list = book.elements();//[书名、作者、售价]

//book.addElement("售价").setText("45元");此处不能用setText()方法，其返回值为void。
Element price = DocumentHelper.createElement("售价");
price.setText("45元 ");
price.setAttributeValue("id", "111");

//此处添加一个标签是对list集合的操作,将售价添加到第二个位置，第三个位置的值自动向后移。
list.add(2, price);

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");
XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
writer.write( document );
writer.close();
}

//删除指定的标签。
@Test
public void delete() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book.xml"));

Element book = (Element) document.getRootElement().elements("书").get(1);
Element price = (Element) book.elements("售价").get(0);
price.getParent().remove(price);

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");
XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
writer.write( document );
writer.close();
}

//更新指定的标签
@Test
public void update() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book.xml"));

Element book = document.getRootElement().element("书");
book.element("售价").setText("88元");

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");
XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);
writer.write( document );
writer.close();
}
}